Apple has released the first developer preview of Mac OS X Lion and updated its information page on the operating system.
With this announcement comes new information on Lion's features, including AirDrop, which allows for zero-configuration, wireless file sharing between Macs; a global auto-save, which saves your work for you and Versions, which automatically saves versions of documents you're working on and provides a Time Machine-like interface for browsing them.
Mail.app has also been re-hauled and closely resembles Mail on the iPad.
Apple's Lion features page has been updated with additional information. With Mission Control, Launchpad and full-screen apps, the Mac OS is looking more like is younger sibling, iOS, than ever.
Paid Mac dev center participants can download copies of Mac OS X Lion from the Mac App Store by requesting a redemption code from their developer account. One code is generated per account, and the "purchase" is stored and associated with that account for any future re-downloads.
If you are a developer, and have access to the preview release, make sure you carefully check the system requirements before installing Lion; you'll need a 64-bit Intel-based Mac running Mac OS X Snow Leopard 10.6.6 or later. You will be able to install Lion on computers registered to your account, but Apple recommends that you use a separate partition or a computer that is dedicated to Lion-only development.
Specific details about the new OS beyond Apple's press releases remain behind the NDA wall. You may discuss the new OS on Apple's developer forums.